A molecular dynamics study on water desalination using single-layer MoSe2 nanopore

Abstract

Development of low-cost and high-efficiency seawater desalination technologies is critical for solving the global water crisis. In this study, we proposed a fast water filtering method, with a high salt rejection rate, that uses MoSe2 nanopore via molecular dynamics (MD) simulation. These simulation results suggest that fast water filtering and high salt rejection rates can be achieved using MoSe2 nanopore with a pore size of 66.54 Å2. Water permeation through the MoSe2 nanopore is larger than that through the MoS2 nanopore of various size, and the water flux through both MoSe2 and MoS2 nanopores is much larger than that through the graphene nanopore of similar nanopore size. The underlying mechanism of water transportation through both MoSe2 and MoS2 nanopores are discussed after analysis of the water permeation potential of mean force (PMF), the 2D density of the water molecule inside the nanopores, the dipole of water molecules during transportation, etc. Our results suggest that a 1-cm2 MoSe2 nanopore (66.54 Å2) membrane can produce freshwater with a flow rate of 10.1 L per day per MPa under 150 MPa, which it is about 2 orders of magnitude higher than the currently used commercial reverse osmosis (RO) membrane.